Pharmaceutical preparations which after administration enter, upon their biological degradation, into the citric acid cycle or belong to it are acquiring greater and greater therapeutic valve, generally in high doses, since it is possible to mitigate or cure cryptogenically induced diseases with them.
Thus, fumaric acid impedes the growth of the Ehrlich ascites tumor in mice, reduces the toxic effects of mitomycin C and aflotoxin (K. Kuroda, M. Akao, Biochem, Pharmacol. 29, 2839-2844 (1980)/Gann. 72, 77-782 (1981)/Cancer Res. 36. 1900-1903 (1976)) and has an anti-psoriatic as well as antimicrobic action (C. N. Huhtsnen, J. Food Sci. 48, 1574 (1983)/M. N. Islam, U.S. Pat. No. 4,346,118 issued Aug. 24, 1982/C.A. 97, 161317b (1982)).
High doses of umaric acid or its presently known derivatives such as dihydroxy fumaric acid, fumaramide and fumaronitrile have such an unacceptable rate of adverse effects and high toxicity upon parenteral, dermal and, in particular, peroral adminstration (P. Holland, R. G. White, Brit, J. Dermatol. 85, 259-263 (1971)/M. Hadedorn, K. W. Kalkoff, G. Kiefer, D. Baron, J. Hug, J. Petres, Arch. Derm. Res. 254, 67-73 (1975)), that up to now it has been necessary in most cases to refrain from such therapy.
In European Patent Application No. 85 116 011.9 of Dec. 16, 1985, fumaric acid derivatives and pharmaceutical preparations containing them have already been described for the treatment of psoriasis.